The Integrated Approach to Permeability Adjustment Based on the Simultaneous Well Log and Well Test Interpretation

Abstract

Nowadays, efficient field development cannot be imagined without the integrated interpretation of field data with different scale – core, well logs, and formation testers. The above mentioned methods allow definition of permeability values, which can be used during the geological and simulation modeling. However, it should be highlighted that there is no unified approach to permeability adjustment which may lead to unclear connections between absolute gas permeability (core, log) and effective permeability (well test) in reservoir models. As a result correct quantitative description of field development parameters could be questioned. The present work considers the creation of the workflow for adjustment of core and therefore logs absolute permeability on field values, estimated from formation testing operations. It can be expected that the adjusted permeability values will describe the filtration process more correctly. During the workflow creation the field with clastic deposits and special logging complex was analyzed. The permeability adjustment workflow, which consisted of several steps, was developed. First of all, absolute log permeability values were obtained taking types/facies into account. Then continuous log effective permeability curves were estimated based on the equations, derived during the analysis of PVT-properties and SCAL data. Finally, the comparison between log and well test permeability was performed. It has been discovered that the developed methodology can be valid for clastic field with unconsolidated deposits. The transformation from average well test permeability to continuous log effective permeability was mathematically validated. Furthermore, it was shown that estimation of continuous fractional flow values can be performed for several intervals. Besides, calculated log mobility can be used for prediction of layers for which water filtration process can be faster. The results, which were obtained during the workflow application, are planned to use during further simulation modeling. This can provide the improvement of development process prediction during the simulation modeling and future field development.